Greywater Research Articles

Assessing the grey water footprint of pesticide use in the Mendoza wine region (Argentina): implications for sustainable water resources management

This paper assesses the impact of viticulture on water resource quality in the Mendoza wine region using the grey water footprint (GWF) approach to estimate the amount of water required to dilute pesticides commonly used in local vineyards. Our analysis indicates that to progress towards sustainable water management in viticulture, limiting or replacing pesticides with high GWF values is essential. We provide detailed results for 24 fungicides, 7 insecticides, and 7 herbicides, assessed at both microregion and district levels, offering insights into pesticide impacts across both detailed and broader spatial scales. At the microregion level, the herbicide Fluroxypyr-meptyl was found to have the highest GWF (1.10 m³ kg-1), followed by the fungicide Fosetyl-aluminium (0.59 m³ kg-1) and the insecticide Imidacloprid (0.41 m³ kg-1). Our findings also show that pesticide impacts vary at the district level, highlighting the need for localised management strategies. Additionally, the significant variability in GWFs at the local level underscores the necessity for region-specific water quality standards to more accurately assess and manage the environmental impact of pesticide use. This study provides a framework for similar assessments in other viticultural regions, aiding in the development of more informed pesticide management to enhance water resource sustainability.

Multi-Dimensional Assessment, Regional Differences, and Influencing Factors of Agricultural Water Pollution from the Perspective of Grey Water Footprint in Zhejiang Province, China

The implementation of differentiated governance for agricultural water pollution (AWP) plays a significant role in alleviating the pressure on agricultural water resources. However, research that comprehensively assesses AWP and its influencing factors from a multidimensional perspective remains relatively limited. This study utilized the grey water footprint (GWF) model to quantify the agricultural grey water footprint (AGWF), agricultural grey water footprint efficiency (AGWFE), agricultural grey water footprint intensity (AGWFI), and agricultural water pollution level (AWPL) in Zhejiang from 2010 to 2020. Subsequently, we applied the standard deviational ellipse (SDE), the kernel density estimation (KDE), and the Dagum Gini coefficient to delve into the dynamic evolution and regional disparities of these indicators. Ultimately, we leveraged both the random forest model and the panel regression model to identify and examine the key factors shaping AGWF-related indicators. The results show that: (1) From 2010 to 2020, in Zhejiang, both AGWF and AGWFI exhibit a trend of first increasing and then decreasing, peaking in 2012. In contrast, AGWFE has consistently increased over the years, reaching an increase of 54.56 CNY/m3 by 2020. Meanwhile, despite fluctuations, AWPL in Zhejiang shows an overall gradual decline. (2) The centroids of relevant indicators for AWP in Zhejiang are primarily located in Jinhua (for AGWF and AGWFI), Shaoxing (for AWPL), and in the area where AGWFE converge. (3) Compared to 2010, the regional disparities in AGWF and AWPL have shrunk significantly in 2020, whereas the regional differences in AGWFE and AGWFI have increased to some extent. In most years, the regional disparities in AGWF, AGWFI, and AWPL are more pronounced in Northeastern Zhejiang compared to the southwestern part. (4) The influencing factors of AGWF, AGWFE, and AGWFI exhibit significant regional heterogeneity. In Northeastern Zhejiang, the primary factors influencing them are technological innovation, resource endowment, and crop-cultivation methods. Conversely, in the southwestern region, the primary factors exerting the same influence are the application intensities of fertilizers, pesticides, and agricultural film application. The primary drivers of AWPL in Zhejiang are grain yield, water resource availability, and crop-planting structure. Notably, these factors do not exhibit regional heterogeneity. The paper proposes AWP control policies from both a comprehensive and multi-dimensional perspective.

A multiobjective optimization model for allocating water quantity and quality in the Yangtze and Yellow River basins

Rapid urbanization and industrial growth have led to water quantity and quality problems. Most current water allocation models focus solely on physical water and neglect the optimization of the water quantity and quality considering the water footprint. Therefore, this study aimed to establish an optimal water resource allocation model for industrial sectors based on the water footprint to identify the most effective strategies for determining the water quantity and quality distribution in river basins. First, we constructed an improved water footprint accounting system using input‒output tables to quantify the total water footprint, grey water footprint, and virtual water trade. Second, we constructed a multiobjective optimal water resource allocation model by considering the water footprint as a decision variable and combining regional economic development and productivity differences. Finally, we compared the water allocation results obtained for the Yellow River Basin, a typical “water-quantity water-scarce region” in China, with those of the Yangtze River Basin, a “water-quality water-scarce region.” The results indicate that the total water footprints of the Yellow and Yangtze River Basins were 211.37 and 317.83 billion m³, respectively, prior to optimization. After optimization, the footprints were 199.54 and 306.03 billion m³, respectively. Water resources have been reallocated through virtual water trade strategies to effectively alleviate both water quantity and quality problems. Virtual water trade strategies have emerged as policy tools capable of mitigating mismatches between industrial systems and regional water resource allocation and providing a solution to physical–virtual water system challenges within river basins.

Comparative investigation on water fouling characteristics in 5 mm and 7 mm tubes with smooth type and screwed type

Application of copper tubes with the diameter of 5 mm instead of 7 mm in chillers of central air conditioning systems is the development tendency due to the requirement of copper material saving. However, the heat transfer deterioration by water fouling precipitated in 5 mm tubes may be more serious than that in 7 mm tubes. The purpose of this paper is to comparatively investigate the water fouling characteristics on both 5 mm and 7 mm tubes. An accelerated experimental method of water fouling process was designed to quickly evaluate the fouling degree. Four tube types are tested, i.e. a 7 mm smooth tube, a 7 mm screwed tube, a 5 mm smooth tube and a 5 mm screwed tube, and these tubes are fabricated as flexible coiled tubes with total length of 200 cm. The results show that the water fouling process experiences the initiation, growth and stabilization stages in sequence, and the crystal form of fouling is in the vaterite, aragonite and schistosity patterns respectively. The fouling masses in 5 mm smooth tube and 5 mm screwed tube are respectively 42.1% and 16.9% larger than those in 7 mm smooth tube and 7 mm screwed tube, meaning that 5 mm tubes are more prone to form water fouling compared with 7 mm tubes; while the averaged fouling mass in screwed tubes is 2.8% lower than that in smooth tubes since screwed tubes are benefit to destroy the integrality of fouling layer and enhance the removal of deposited particulates.

Assessing the suitability of agro-waste consortium in greywater treatment: A sustainable strategic exploration

Assessing the suitability of agro-waste consortium in greywater treatment: A sustainable strategic exploration

Consequential life cycle assessment of urban source-separating sanitation systems complementing centralized wastewater treatment in Lund, Sweden

This study examined various source-separating sanitation systems to evaluate their environmental performance, providing decision-makers with insights for selecting an appropriate system for a newly developed neighborhood in Sweden. A full consequential LCA was conducted to account for resource recovery and substitution. The local wastewater treatment plant WWTP was modeled as a reference. Secondly, a urine recycling system was introduced to treat 75% of the collected urine, with the remainder piped to the WWTP. Thirdly, a black and greywater (BW&GW) treatment system handling all generated wastewater was examined. Finally, a hybrid source-separating system combining urine, black, and greywater was investigated. The results indicated that the four scenarios exhibited global warming potentials (GWP) of 78, 62, 32, and 24 kg CO2-eq per PE/ y. Recycling urine as fertilizer led to a 20% reduction in the GWP of the reference. It also reduced other impact categories, with a 55%, 65%, and 45% reduction in eutrophication, ozone depletion, and acidification, respectively. The BW&GW system achieved a 60% reduction over the reference GWP, mainly due to fertilizer, biogas, and cleanwater recovery. Integrating urine, black, and greywater recycling in the final scenario achieved a 25% reduction compared to the BW&GW scenario, primarily due to lowering of the ammonia stripping GWP and the additional fertilizer recovery. Based on sensitivity analyses, switching citric acid for sulfuric acid reduced the GWP of the urine stabilization unit process by 101%, from 15.47 to -0.14 kg CO2-eq per PE/ y. Ultimately, the findings suggest that the fully decentralized source-separating sanitation system incorporating urine, blackwater, and greywater recycling, particularly when combined with 70% energy recovery at the urine concentrator, is most favorable.

Performance of Agricultural Wastes as A Biofilter Media for Low-Cost Greywater Treatment Technology

Performance of Agricultural Wastes as A Biofilter Media for Low-Cost Greywater Treatment Technology

Nitrogen cycling and associated grey water footprint in croplands under different irrigation practices

The pervasive application of nitrogen (N) fertilisers in agriculture poses a significant threat to freshwater ecosystems. The grey water footprint (GWF) is a measure of the volume of freshwater required to assimilate the relative water pollutants resulted from N leaching-runoff processes. The responses of N cycling and associated regional GWF to crop production under different irrigation methods have not been investigated. In this study, the N leaching-runoff rate, N₂O, and NH₃ emissions in croplands and the associated GWF per unit crop yield (UGWF) and annual total GWF (TGWF) of winter wheat-summer maize crop rotations across the Hebei, Shandong, and Henan Region (HSHR) of China were simulated and evaluated at the prefecture level over the 2004–2020 period. Four irrigation scenarios were modelled: furrow, sprinkler, surface drip, and subsurface drip irrigation. The results showed significant spatial and temporal heterogeneity in N leaching-runoff rates and emissions of N2O, and NH3. The N leaching-runoff rates for winter wheat and summer maize ranged from 3.9% to 10.9% and 15.0%–32.3%, respectively. With changing different irrigation methods, N leaching-runoff rates exhibited greater sensitivity than N₂O and NH₃ emissions; this sensitivity was more pronounced in winter wheat than in summer maize. Findings reveal that N pollution is influenced not only by irrigation methods but also by weather conditions, crop-specific rooting characteristics, sowing time, and soil texture. Winter wheat UGWF under the four irrigation methods mostly followed the order of furrow > sprinkler irrigation > surface drip irrigation > subsurface drip irrigation. Conversely, for summer maize, subsurface drip irrigation resulted in a higher UGWF compared to furrow irrigation, mainly due to increased water percolation thus higher N leaching-runoff rate in near-saturated soil with higher rainfall. This result reveals the potential conflict between water-saving irrigation and N pollution control. This analysis underscores the necessity of recognising the combined effects of agricultural management practices on water conservation and environmental safeguarding.

Poly (acrylic acid-co-2-hydroxyethyl methacrylate)-grafted gum ghatti hydrogel for capturing heavy metal ions

In this work, a facile route is explored for the synthesis of a novel polymer composite-based hydrogel (PC-hydrogel). The ratio of 2-(Hydroxyethyl) methacrylate (HEMA) and acrylic acid (AA) is optimized first based on Fourier transform infra-red spectroscopy, swelling ratio (SR%) and surface negative charge (PZC). Results indicate that PC-hydrogel composed of copolymer of HEMA: AA in 1:4 ratio is optimized, for grafting on Gum ghatti (Gg) during free-radical graft copolymerization process. Among all other possible combination of HEMA: AA, 1:4 ratio grafted Gg is termed as PC-hydrogel [Poly (AA-co-HEMA)-g-Gg]. PC-hydrogel exhibited negative surface charge over a wide range of pH owing to increase in AA. The swelling (g/g) and water retention ratio (%) of the prepared hydrogel have been found to be 342.6, 385 & 412.6 g/g and 74.83, 65.30 & 57.86 % in grey, tap and distilled water respectively. Furthermore, PC-hydrogel is applied for capturing Cu2+ and Co2+ ions in aqueous phases. Experimental results showed that adsorption process was pH-dependent, and the maximum capturing of Cu2+ and Co2+ was observed at neutral pH 7. Among different adsorption isotherms models like Langmuir, Freundlich, and Temkin models, experimental data fitted closely with the Langmuir adsorption model showing a maximum adsorption capacity of 381.67 and 328.94 mg/g for Cu2+ and Co2+ respectively. The capturing of metal ion followed pseudo-second-order rate model [rate constant k = 1.7 x 10−4 for Cu2+ and 1.5 x 10−4 for Co2+ g/(mg.min)]. The PC-hydrogel property retained its uptake capacity of metal ions up to the three successive adsorption−desorption cycles, and exhibited higher selectivity towards Cu2+ and Co2+ and other (NaCl, MgCl2, CaCl2) coexisting ions.

Performance of an integrated household greywater treatment system for water optimization and reuse

This study evaluated the efficiency of an on-site household greywater treatment system for indirect human reuse and for domestic lawn irrigation. This helps in the reduction in the disparity between water demand and supply that is facing the rapidly increasing global populace. Natural household greywater was settled and then conventionally filtered by using two types of non-woven geotextile media; thermally bonded and needle punched. A third woven cotton textile media was also experimented and all the non-woven geotextile media were tested in single and double layers and combined with the woven cotton textile layer. The different filter media configurations were tested for a period of one year operation (six runs) with two filtration rates of 15.00 and 25.00 m3/m2/day for each run. For all runs, the final treated effluent was disinfected using calcium hypochlorite prior to reuse. The double layer needle punched non-woven geotextile media together with the woven cotton textile media gave the best removal efficiencies; 96.34 ± 1.85% for turbidity 81.87 ± 6.43% for BOD5, 97.49 ± 1.68% for TSS, 75.35 ± 3.99% for CODt, 99.59% for E.coli. The soluble CODs removal efficiencies were negligible (below 3%) in the first four runs with non-woven geotextile media and increased to 28.05 ± 4.29% when the woven cotton textile media was added. In general, the system was found to save about 63% of the daily water consumption reflecting a net 22.50% reduction in the daily water billing costs for the whole household.

Use of native macrophyte Echinodorus subalatus for grey water treatment applying alternative bed substrate in constructed wetlands

ABSTRACT Two vertical flow constructed wetland (VFCW 1 and VFCW 2) with native macrophyte Echinodorus subalatus (Mart.) were operated. In VFCW 1, the substrates used were ceramic brick, washed sand, seashells (Anomalocardia brasiliana), and ceramic brick and sand in VFCW 2. The system was operated for 74 days, in batches, with cycles of 168 h, and fed with synthetic grey water. The presence of seashells in VFCW 1 was a differential factor (p < 0) for the removal of anionic surfactant (94.09 ± 7.77%), COD (88.43 ± 5.43%) and total phosphorus (45. 98 ± 9.86%) when compared to VFCW 2. The Langmuir isotherm was used to calculate the substrate adsorption capacity for total phosphorus, anionic surfactant, and COD. The results showed that adsorption on support materials was not the primary mechanism of pollutants removal. From 16S sequencing, it was observed that phylum Firmicutes was the most abundant (96.5%), followed by phylum Proteobacteria (3.5%). The results suggest that using seashells as an alternative substrate improved pollutant removal efficiency.

Greywater irrigation of pepper plants: Possible application and its impact on soil and plant growth

AbstractGreywater reuse may be considered a water source that can compensate for water scarcity. Reusing treated greywater on fields instead of disposing of it would be more environmentally friendly. The objective of this study was to investigate the physiological response of pepper plants to the application of both untreated and treated greywater. The greywater obtained from Al‐Huson University College was treated with zeolite filters before being used for plant irrigation in the experiments. The electrical conductivity (EC), total dissolved solids (TDSs) and chemical oxygen demand (COD) of greywater were all higher than those of tap water by 44%, 68% and 509%, respectively. The results demonstrated that plants irrigated with tap water and treated with greywater presented greater fruit and biological productivity than did those irrigated with untreated greywater. The use of treated greywater led to a notable 8.3% increase in overall chlorophyll levels. Irrigation of pepper plants with untreated greywater led to a 33% increase in electrolyte leakage. The plants irrigated with greywater presented the highest levels of proline and total soluble sugars. Compared with those in all the other water treatments, the plants irrigated with greywater presented significantly greater magnesium and salt concentrations. Typically, treated greywater has the most significant impact on agricultural productivity.

A novel framework reveals anthropogenic stressors of phosphorus polluted river-lake connection water system in Poyang lake basin of China

Poyang lake (PYL), as China's largest freshwater lake, has been suffering from increasing total phosphorus (TP) pollution associated with rapid basinal socio-economic development. However, anthropogenic phosphorus stressors were rarely examined in PYL basin due to its large-scale and complex river-lake connection water system, hampering phosphorus pollution control efforts. In this study, water pollution stress from multiple anthropogenic activities is quantitatively examined in PYL basin based on a newly developed framework coupling grey water footprint (GWF) analysis with the SPARROW model. Results show that the phosphorus source-sink process in PYL basin has been well simulated by SPARROW model quantifying an overall TP delivery rate of 0.39, with catchments closer to PYL showing higher delivery rate of phosphorus (up to over 0.8). The GWF analysis demonstrates that anthropogenic phosphorus sources have imposed much higher pollution stress on PYL than its inflowing rivers, with twelve catchments nearby PYL identified as critical source areas of TP contamination. Agricultural farming, livestock & poultry production, and urban household are recognized as the dominant anthropogenic stressors burdening water environment of PYL. Based on these, policy recommendations are provided for advancing control of the phosphorus pollution stressors. The methodology is effective in refined examination of water pollution sources, which is expected to be applied in other watersheds providing informative diagnosis of water issues especially in lakes.

Navigating the path: regulatory readiness and stakeholder insights in Indonesia's citywide inclusive sanitation landscape

Inadequate sanitation has catastrophic consequences for public health, standard of living, and productivity, as well as gender equality and social inclusion. Urban sanitation programmes yield suboptimal outcomes regarding long-term impact, effectiveness, sustainability, and fairness. To ensure that all urban dwellers in Low- to Middle-Income Countries (LMICs) have access to sanitation facilities that are properly maintained and safe, it is crucial to bring about a fundamental change in the urban sanitation sector through the implementation of Citywide Inclusive Sanitation (CWIS). This research analyses the sanitation regulatory framework and stakeholders' perspectives in Bandung City, Indonesia. The goal is to determine the possible obstacles and advantages of implementing a comprehensive CWIS (Citywide Inclusive Sanitation) system in Indonesia. The CWIS idea has been recognised at the national level in Indonesia. While existing legislation and policies partially govern and deal with CWIS components, there is no official programme establishment yet and limited implementation at the local level. Some challenges that have been identified include conflicting priorities in serving marginalised populations, a lack of political commitment and capacity to provide comprehensive services for all types of domestic wastewater (including grey water) and throughout the entire sanitation service chain (from containment to treatment and/or reuse and recovery), inadequate knowledge management and data transparency, a lack of incentives and penalties for local governments to meet sanitation standards, and limited motivation for meaningful and institutionalised private sector involvement. This study also delineates four crucial domains for efficiently fostering the deployment of CWIS in Indonesia.

Lepidium peruvianum as a Source of Compounds with Anticancer and Cosmetic Applications

Lepidium peruvianum—an edible herbaceous biennial plant distributed in the Andes—has been used for centuries as food and as a natural medicine in treating hormonal disorders, as an antidepressant, and as an anti-osteoporotic agent. The presented study aims to prove its beneficial cosmetic and chemopreventive properties by testing the antiradical, whitening, cytotoxic, and anticancer properties of differently colored phenotypes that were extracted using three solvents: methanol, water, and chloroform, with the help of the chemometric approach to provide evidence on the impact of single glucosinolanes (seven identified compounds in the HPLC-ESI-QTOF-MS/MS analysis) on the biological activity of the total extracts. The tested extracts exhibited moderate antiradical activity, with the methanolic extract from yellow and grey maca phenotypes scavenging 49.9 ± 8.96% and 48.8% ± 0.44% of DPPH radical solution at a concentration of 1 mg/mL, respectively. Grey maca was the most active tyrosinase inhibitor, with 72.86 ± 3.42% of the enzyme activity calculated for the water extract and 75.66 ± 6.21% for the chloroform extract. The studies in cells showed no cytotoxicity towards the human keratinocyte line HaCaT in all studied extracts and a marked inhibition of cell viability towards the G361 melanoma cell line, which the presence of pent-4-enylglucosinolate, glucotropaeolin, and glucoalyssin in the samples could have caused. Given all biological activity tests combined, the three mentioned compounds were shown to be the most significant positive contributors to the results obtained, and the grey maca water extract was found to be the best source of the former compound among the tested samples.

Enhancing Greywater Treatment: High-Efficiency Constructed Wetlands with Seashell and Ceramic Brick Substrates

Constructed wetland (CW) systems have been recognized as a sustainable technology for wastewater treatment that can be easily integrated into the local natural environment, offering both low cost and high efficiency. In this study, synthetic greywater was treated using a vertical subsurface flow CW operated in batch mode with 7-day cycles across two phases, operated in parallel: I, non-vegetated, and II, vegetated, with Echinodorus subalatus. The mixed filter bed was composed of seashells, ceramic brick fragments, and sand. No statistically significant differences (p &gt; 0.05) were observed between the non-vegetated and vegetated phases for most parameters. The removal efficiencies of organic matter, anionic surfactants, and total phosphorus in the non-vegetated versus vegetated phases were (91.0 ± 3.8)% versus (94.0 ± 1.1)%; (71.9 ± 14.1)% versus (60.0 ± 9.5)%; and (35.2 ± 4.6)% versus (40.2 ± 15.5)%, respectively. Phosphorus removal exceeded values reported in the literature for both phases, primarily due to the calcium present in the seashells, which increased the electrical conductivity and hardness of the effluent compared to the influent. The macrophyte exhibited leaf desiccation, possibly due to contact with greywater and its young age (30 days), which may have negatively impacted the system’s performance during the vegetated phase.

Optimizing greywater treatment in green walls: A comparative analysis of recycled substrate materials

The utilization of green walls for on-site greywater treatment in urban buildings has garnered significant attention in recent research, with substrates playing a vital role in treatment performance. The incorporation of recycled materials as substrates not only offers a cost-effective solution for greywater treatment, but also enhances sustainability by repurposing wastes. This study investigates the efficacy of three recycled substrates: alum sludge, garden compost, and a mixture of perlite-coconut fiber in three green wall systems for greywater treatment. Each substrate was allocated to a three-pot column. Comparative analysis revealed alum sludge (C3) and the coconut fiber-perlite mix (C1) achieving the highest chemical oxygen demand (COD) removal at 89.45 ± 2.92 % and 89.34 ± 2.47 %, respectively, with garden compost (C2) recording 67.98 ± 7.45 %. For total nitrogen (TN) removal, C2 achieved the lowest efficiency (49.27 ± 9.39 %), while C1 demonstrated 83.79 ± 10.45 %. Notably, C3 exhibited superior total phosphorus (TP) removal at 94.86 ± 1.87 %, compared to 52.07 ± 17.88 % for C1 and 24.90 ± 30.95 % for C2. Our findings demonstrate that substrate selection is crucial for optimizing both pollutant removal and plant health in green walls. The coconut fiber mix emerged as the most effective substrate, supporting robust plant growth and superior pollutant removal, particularly for nitrogen removal. In contrast, garden compost proved unsuitable, with minimal plant survival post-greywater introduction. Alum sludge showed significant promise, particularly for TP removal, reinforcing its effectiveness in green walls. These insights underscore the importance of substrate optimization in greywater treatment systems in urban environments.

Experimental study based on the usage of polymers for greywater treatment

Water scarcity presents a pressing challenge in Egypt, exacerbated by factors such as population growth, urbanization, and climate change impacts. With over 95% reliance on the Nile River for freshwater supply, Egypt's water resources are strained, particularly with a population exceeding 100 million. Egypt's arid climate intensifies water scarcity, necessitating sustainable management strategies. This study explored greywater treatment as a solution to alleviate water scarcity in Egypt, investigating its technical feasibility, economic viability, and environmental benefits. Greywater, derived from domestic activities, is an underutilized resource that can be reclaimed and treated for reuse, reducing demand for freshwater sources. Through greywater treatment systems, households and communities can recycle water, conserve resources, and mitigate pollution. The study investigated using polymers as a coagulant in greywater treatment, examining its efficacy in removing contaminants and improving water quality. Experimental trials were conducted to evaluate the performance of polymer addition in greywater treatment compared to conventional methods. Results demonstrate that polymer addition reduces turbidity, suspended solids, and organic pollutants in greywater. Poly aluminum chloride (PAC) polymer, in particular, exhibits strong coagulation capabilities, versatility across pH ranges, and high efficiency in contaminant removal. Additionally, PAC offers operational advantages such as low dosage requirements and reduced sludge production.

Use of Vertical Greenery Systems for the domestic scale treatment of greywaters for fit-for-purpose reuse. Applicability and future prospects.

Abstract Only less than 1% of the Earth’s water is fit for human activities. Domestic consumption accounts for roughly 20% of all uses of water, adding pressure to the increasing water scarcity stress. Water intakes of residential buildings for all everyday uses are constituted by a high-quality resource, which is either costly to produce or conspicuous in amounts to withdraw from natural sources. The present proposal aims to test the feasibility of the application of decentralized greywater treatment strategies, based on the use of vertical greenery systems integrated into residential buildings to assess both the optimal scale of application in residential settlements and a comparative analysis on reclaimed water resource savings. The aim is to promote the circular use of water resources by allowing for fit-for-purpose employment, thus reducing the overall intake due to the residential sector. The methodology hereby proposed has been developed using as a case study the most widespread residential typologies in the Southern Italian context, such as single detachment, row houses, low and medium-rise apartment buildings. The result is the proposition for each residential typology of a retrofitting strategy that employs the integration of a green infrastructure inside the residential spaces. Until now, the Mediterranean context has been characterized by limited use of strategies directed towards the efficient employment of water resources, since the mild climatic conditions have always provided for an adequate amount of freshwater. Therefore, limited studies have been carried out on the application of those strategies in Mediterranean landscapes. However, the rapid shift in precipitation patterns due to climate change has defined the need to quickly embrace new strategies, systems, and technical solutions for improving water use efficiency and promoting reuse.

Efficient and sustainable removal of linear alkylbenzene sulfonate in a membrane biofilm: Oxygen supply dosage impacts mineralization pathway

Linear alkylbenzene sulfonate (LAS) can be thoroughly mineralized within sufficient oxygen (O2), but which is energy intensive and may causes serious foaming problem. Although cometabolism can achieve efficient LAS removal within a wide range of O2 dosages, how O2 dosage systematically affects LAS metabolic pathway is still unclear. Here, membrane aerated biofilm reactor (MABR) enabled accurate O2 delivery and bulk dissolved oxygen (DO) control. MABR achieved efficient removal of LAS (>96.4 %), nitrate (>97.8 %) and total nitrogen (>96.2 %) at the three target DO conditions. At high DO condition (0.6 mg/L), LAS was efficiently removed by aerobic mineralization (predominant) coupled with aerobic denitrification biodegradation with the related functional enzymes. Pseudomonas, Flavobacterium, Hydrogenophaga, and Pseudoxanthomonas were dominant genus contributing to four possible LAS aerobic metabolic pathways. As O2 dosage reduced to only 29.7 % of the demand for LAS mineralization, O2 facilitated LAS activation, benzene-ring cleavage and a portion of respiration. NO3--N respiration-induced anaerobic denitrification also contributed to ring-opening and organics mineralization. Desulfomicrobium and Desulfonema related two possible anaerobic metabolic pathways also contributed to LAS removal. The findings provide a promising strategy for achieving low-cost high LAS-containing greywater treatment.